FG 260 is a grey iron grade under Indian Standard IS 210, and SG 500/7 is a ductile iron grade under IS 1865. EN-GJS is the European naming for ductile iron under EN 1563, and EN-GJL is the European naming for grey iron under EN 1561.
In each case the numbers are minimum mechanical properties. Once you can read them, you can compare drawings from different countries and spot a mismatch before it reaches the foundry.
Reading the Indian grades
- FG stands for flake graphite, meaning grey iron. FG 260 means a minimum tensile strength of 260 MPa on a test bar.
- IS 210 covers a range of grey iron grades, from lower-strength FG 150 to higher-strength FG 400.
- SG stands for spheroidal graphite, meaning ductile iron. SG 500/7 means a minimum tensile strength of 500 MPa and a minimum elongation of 7%.
- IS 1865 covers ductile grades from highly ductile ferritic grades to high-strength pearlitic ones.
Reading the European grades
The European names follow the same logic. EN-GJS-500-7 means ductile iron with 500 MPa minimum tensile strength and 7% minimum elongation, so it lines up closely with SG 500/7. EN-GJL-250 means grey iron with 250 MPa minimum tensile strength.
Older drawings may still use earlier national names, such as GGG for ductile iron and GG for grey iron in German drawings. A foundry should be able to tell you which current grade it treats as the replacement.
American drawings use ASTM A48 for grey iron, named by class, and ASTM A536 for ductile iron, named by tensile, yield and elongation in imperial units. The grades do not map one to one onto the European ones, so ask the foundry to confirm which standard it will test to.
What a grade does not tell you
A grade fixes minimum properties on a test bar, not the properties everywhere in your part. Thick sections cool slowly and can come out weaker than the bar. Some standards address this with separately cast, cast-on or relative-wall-thickness test pieces, so your drawing should say which applies.
A grade also does not fix hardness, nodularity, matrix structure or chemistry limits unless you add them. These are covered in writing a specification for an SG iron casting.
Practical checks
- Write the full standard and grade on the drawing, for example "EN-GJS-500-7 to EN 1563", not just "SG iron".
- Ask the foundry to name the grade it will cast and the standard it will test to.
- Ask for a material test certificate showing tensile, elongation and chemistry for each heat, as explained in what an EN 10204 3.1 certificate is.
- Check the certificate against the drawing grade, not just the metal family.
- Ask what test piece the results come from, because a separately cast bar may not reflect a thick section of your part.
Next step
We check that the grade on the order, the test report and the drawing all match before a casting ships. To review your drawings and grades, book a free sourcing review.